This invention relates to a method and apparatus for vacuum evacuation and pressure filling of sealed pin joints with lubricant. More particularly, it is concerned with a method and apparatus providing a charging gun adapted to be manually positioned in communication with a chamber to be evacuated and a sequence timing and shutoff mechanism for controlling evacuation of the chamber and subsequent filling with lubricant. Vacuum checking for seal leakage prior to filling is also a provision of the system.
Many of the rotating and oscillating joints on earthmoving and industrial machinery are sealed and provided with a reservoir chamber to contain sufficient oil or other lubricant for extended periods of operation. Frequently, a portion of the reservoir chamber includes cavities closed by seals and bearings as well as the passages connecting such cavities with the chamber. One of the problems encountered with such joints has been the inability to completely fill the reservoir with oil due to air being trapped in inaccessible places.
Previous attempts to solve the problem thus posed have taken the form of pressure filling of and displacing air from the reservoir using complex bleed procedures. These have not always been entirely effective and satisfactory.
Another problem is that of checking the joints for undesirable leakage prior to filling. Faulty seals at the joints, for example, can cause not only wastage and early depletion of oil from the reservoir but also premature wearing due to foreign matter entering around the seals.